To achieve an equal amount of time for each of the five auspices, approximate percentages of illumination for each of the auspices would be:

Ragabash: 0-9.5492%
Theurge: 9.5492-34.5492%
Philodox: 34.5492-65.4509%
Galliard: 65.4509-90.4509%
Ahroun: 90.4509-100%

I gave an equation to represent the percentage of the lunar disc illuminated (t) days after the astronomical event of the new moon. If you wanted equal time given to each of the auspices, you'd have about 2.9530588 days to either side of the new moon that would belong to the Ragabash, then 2.9530588 days of waxing Theurge, then 1.4765294 days to either side of the first quarter for the waxing Philodox, then 2.9530588 days of waxing Galliard, then 2.9530588 days to either side of the full moon to the Ahroun, then 2.9530588 days of waning Galliard, then 1.4765294 days to either side of the last quarter for the waning Philodox, 2.9530588 days for the waning Theurge, and then we're back at the Ragabash business.

If you want, think of the percentage of illumination of the moon as being represented by a cosine curve. Say, f(t)= -0.5 cos (t(2π/29.530588) + 0.5 as the equation, where (t) is the number of days after the astronomical event of the new moon, and f(t) is the percentage of illumination (running from 0 - the new moon, to 0.5 for the quarters, and 1 for the full moon). A day to either side of the full moon it's still probably at about 0.97, 0.98, 0.99.